1. Field of the Invention
The present invention relates to a liner supporting structure for annular combustor and more particularly to a liner supporting structure suitable for an annular combustor in which a liner and a structural body of a combustor supporting the liner are composed of materials extremely different from each other in linear expansion coefficient.
2. Description of the Related Art
In recent years, as a material of a liner constituting a gas turbine combustor, in place of conventional metallic materials, ceramics materials such as CMC (ceramics matrics composite) excellent in heat resistance have been used. By use of them, cooling air for cooling the liner can be greatly reduced, and the thermal efficiency can be improved, and surplus air can be used for lean combustion, and the discharge amount of nitrogen oxide can be reduced.
Generally, ceramics materials have a smaller linear expansion coefficient than that of metallic materials. Therefore, in an annular combustor, when a liner composed of a ceramics material is to be mounted on a dome composed of a metallic material as conventional, due to a difference in thermal expansion value between the dome and the liner during combustion, a relative displacement is caused between the dome and the liner at the connection between them. Therefore, when the liner is to be composed of a ceramics material, some measure must be taken so as to eliminate the unfavorable effect due to the difference in linear expansion coefficient.
As a measure for eliminating such an unfavorable effect due to a difference in linear expansion coefficient, for example, application of the liner supporting structure of a gas turbine combustor proposed in Japanese Patent No. 2647144 may be considered.
Namely, as shown in FIG. 5, it is a method for holding the plate spring 104 shown in FIG. 6 in the fitting part 103 between the dome (inner cylinder) 101 and the liner (tail cylinder) 102 of the gas turbine combustor 100 and supporting the liner 102 by the dome 101 using the elastic force of the plate spring 104.
However, ceramics materials are generally brittle and have no ductility and strength like metallic materials, so that in the aforementioned support method for acting comparatively large pressing force between the liner 102 and the dome 101, there is a risk that fretting may be generated in the liner 102, or the liner 102 may be destroyed. Further, the plate spring generally has a short stroke of effective elastic deformation, so that there is the possibility that it cannot correspond to a large dimensional difference. Furthermore, even though the support method may perform the support in the radial direction of the dome 101 and the liner 102, it cannot sufficiently cope with external force acting in the circumferential direction and axial direction.
The present invention was developed with such a foregoing problem of the related art in view and is intended to provide a liner supporting structure for an annular combustor for, even when there is a large difference in linear expansion coefficient between the respective materials of a liner and a structural body of the combustor for supporting the liner, eliminating an unfavorable effect due to the difference in linear expansion coefficient and supporting the liner by the structural body of the combustor in a state that each member constituting the combustor is free of damage, and an annular combustor having such a liner supporting structure.
According to the present invention, a liner supporting structure for an annular combustor of which a liner for forming a combustion chamber is connected to a structural body constituting a part of said combustor so that said liner is supported by said structural body, comprises: a flexible connection member of connecting said structural body to said liner, said connection member having a first end positioned on a side of said structural body and a second end positioned on a side of said liner, said second end being disposed on an outer surface of an end part of said liner positioned on said side of said structural body; first fixing means of fixing said first end of said connection member to said structural body; and second fixing means of fixing said second end of said connection member to said end part of said liner.
According to the present invention, an annular combustor comprises: a liner for forming a combustion chamber; a structural body connected to said liner; and a liner supporting structure for connecting said liner to said structural body so that said liner is supported by said structural body, said liner supporting structure including: a flexible connection member of connecting said structural body to said liner, said connection member having a first end positioned on a side of said structural body and a second end positioned on a side of said liner, said second end being disposed on an outer surface of an end part of said liner positioned on said side of structural body; first fixing means of fixing said first end of said connection member to said structural body; and second fixing means of fixing said second end of said connection member to said end part of said liner.
Preferably, said connection member is a flat member.
Preferably, a spacer is disposed between said second end of said connection member and said outer surface of said end part of said liner.
Preferably, a seal ring is slidably mounted on a part of said structural body corresponding to a position between said first end and said second end, an end edge of said liner on said side of said structural body being in contact with said seal ring.
Preferably, said seal ring is disposed at a stepped part formed on said part of said structural body corresponding to said position between said first end and said second end.
Preferably, said seal ring has a surface perpendicular to a central axis of said annular combustor, said end edge of said liner being in contact with said surface perpendicular to said central axis.
Preferably, said seal ring is pressed against said end edge of said liner by an elastic member.
Preferably, said structural body is a dome of said annular combustor.
Preferably, said liner is made of a ceramics material.
According to the present invention constituted as mentioned above, even if there is a large difference in linear expansion coefficient between the materials of the liner and the structural body of the combustor for supporting the liner, and a relative displacement is generated between the two due to temperature changes, the structural body of the combustor can strongly support the liner without applying excessive stress to the liner formed by, e.g., a ceramics material.